I will talk about asymptotic detector operators describing possible measurements performed at null infinity. I will discuss how to define them in terms of light-ray operators in conformal field theories as well as in weakly-coupled field theories, how to compute their matrix elements, and how to renormalize them, leading to detector anomalous dimensions. I will apply this framework to Wilson-Fisher theory as an explicit example, recovering known results, resolving some puzzles, and discovering some novel Regge trajectories. Finally, I will consider detectors and event shapes in asymptotically-flat Einstein gravity.